The aim of this study is to test vesicular stomatitis virus (VSV)-based recombinant virus vaccines to immunize monkeys against measles virus (MV). MV poses a serious threat to human populations being one of the 10 leading causes of death in children: Although a vaccination strategy against MV already exists, its efficacy is limited, and its pitfalls could significantly cpmpromise the goal of MV eradication. MV is present in secretions and is shed on mucosal surfaces and thus the development of mucosal vaccines using VSV vectors is a logical approach. The specific aims of this study are: t. To develop a rhesus macaque (RM) model to test a new measles vaccine using VSV-MV hybrid vector and to compare the efficacy of this vaccine to the classic Edmonston vaccine. We will investigate the correlates of immune protection in RM with a recombinant VSV-measles vaccine expressing the protein H. 2. To test a new strategy of vector administration in order to provide an effective boost of the measles immune response and to circumvent vaccine neutralization by antibodies transferred from seropositive mothers. To develop two new viral vectom to prevent vaccine neutralization. Three different VSV-MV vaccines that do not cross-neutralize each other are available using different VSV vectors in order to test this strategy. We will determine if a novel measles vaccine candidate based on a VSV recombinant is an effective vaccine in RM model even in the presence of maternal antibody.